M. hominis and a related mycoplasma species, Ureaplasma urealyticum, cause about half of all non-gonococcal venereal diseases. In addition, about 70% of patients with a gonococcal infection are concurrently infected with a mycoplasma.
M. hominis is associated with pathological conditions in the urogenital tract of men and the upper urogenital tract of women. For example, M. hominis has been implicated as a cause of nongonococcal urethritis, urethroprostatitis, vaginitis, endometritis, pelvic inflammatory disease, cervicitis, infertility, postpartum septicemia, pregnancy wastage, low birth weights and birth defects.
M. hominis is often transmitted by sexual contact and can be transmitted to neonates born of infected mothers, resulting in infection of fetuses and infants. M. hominis can cause chorioamnionitis, spontaneous abortion of preterm fetuses, skin abscesses, central nervous system infections and fatal fetal pneumonia. (See reviews by Cassell et al. (1991) Clin. Perinatol. 18:241-262; Cassell et al. (1984) Adv. Exp. Med. Biol. 224:93-115; and Cassell et al. (1983) Sex. Transm. Dis. 10:294-302.)
M. hominis lack a cell wall and are among the smallest of free living organisms, having a size of only about 0.2 to 0.3 .mu.m. The genome of M. hominis is unusual in its small size (5.times.10.sup.8 daltons) and low guanine/cytosine content. M. hominis are difficult to culture because of their fastidious nutritional requirements and slow growth rates. Such properties make diagnosis of M. hominis infection by the current bacteriological culturing procedures difficult and time consuming. For example, diagnosis of M. hominis infection by such procedures can require up to 2 to 6 days for positive identification depending on the amount of the initial inoculum. Since diagnosis of M. hominis infection by bacteriological culturing procedures is time consuming, expensive and requires a high degree of expertise, few clinical laboratories include M. hominis in the list of organisms for which they provide detection services. These disadvantages often discourage physicians from requesting diagnostic tests for M. hominis and result in a considerable loss of time in treatment of patients. Consequently, the etiologic role of M. hominis in various diseases and the complete range of tissue tropism for this pathogen has not been elucidated.
M. hominis-specific nucleic acid probes and antibodies offer an approach to surmount the difficulties inherent in identification and detection of M. hominis by traditional bacteriological culture procedures. Rapid and effective immunoassays for M. hominis can dramatically decrease the time and expense of diagnosing M. hominis infection. Specific nucleic acid probes for M. hominis are useful in conventional hybridization detection procedures, as well as in other procedures, such as in situ hybridization, solution hybridization and in vitro nucleic acid amplification with subsequent detection. The latter method for M. hominis detection provides a practical means to enhance detection sensitivity relative to conventional hybridization technology. Moreover, polypeptides which are uniquely encoded within the M. hominis genome have utility as antigens or vaccines against M. hominis.
Although the sequence of the M. hominis 16S ribosomal RNA is known (Weisberg et al. (1989) J. Bacteriol. 171:6455-6467), there has been no publication of a nucleotide or polypeptide sequence which is specific for M. hominis.